Process for cleaning textile fabrics



March 3l, 1 964 1 P. cuRTlN 3,126,555

PEocEss EoR CLEANING TEXTILE FABRICS Filed Oct. 23. 1959 FAB/7l (.5

United States Patent O 3,126,555 PRCESS FOR CLEANING TEXTILE FABRICS Leo P. Curtin, Cranhury, Middlesex County, NJ.; Leo Vincent Curtin, executor of Leo P. Curtin, deceased Filed Oct. '23, 1959, Ser. No. '848,255 4 Claims. (Cl. 8149.1)

This application is a continuation-in-part of my copending application, Serial Number 670,635, filed July 9, 1957, now abandoned.

This invention relates to a novel process for cleaning textile fabrics and it comprises placing the soil textile material in a container which is tightly closed, then building up within the container and soiled fabric a gaseous pressure higher than the pressure against which the gas later will be released, then, without reducing this pressure, introducing a cleaning liquid at a still higher pressure, thus compressing the gas entrapped in the recesses of the fabric into smaller volume, with entry of the cleaning liquid into the interstices and capillary openings cf the fabric, then permitting the compressed gas within the fabric to expand by allowing it to exhaust against a lower gaseous pressure external to the container, thus forcing most of the cleaning liquid out of the fabric and out of the container, said liquid carrying out soil and dirt from the fabric and out of the container, and repeating the cycle as many times as circumstances indicate with fresh cleaning liquid; all as is more fully hereinafter set forth and as claimed.

Cleaning liquids are considered to consist of, (a) the so-called dry-cleaning liquids, for example, trichlorethylene, carbon tetrachloride, benzene, petroleum spirits, and the like, and (b) detergent solutions, for example, solutions of the sodium salts of fatty acids, or soaps, the various non-ionic and anionic detergents of synthetic origin, and various equivalent materials. The detergent solutions used in the present process are usually followed by a water rinse and this is accomplished by replacing detergent solution in the cycle by water. The dry-cleaning types of course need no water rinse, the last cycle of organic liquid serving this purpose.

The process herein described may be carried Out by an assemblage of mechanisms, for example, pumps, aircompressors and the like, all of which perform their usual, expected functions. The present invention, therefore, resides in a new principle, method or process for the cleaning of textile fabrics and not in the means for carrying out the process.

It will be obvious that the process may be carried out, wholly or in part, with pressures below atmospheric but usually there is no advantage in such an arrangement. Likewise, it is possible to use one of a variety of gases. Air, however, is entirely satisfactory and the invention will be described with pressures at atmospheric and above and with air as the gas used in the process.

In a simple embodiment of my invention, the soiled textile material is placed in a suitable vessel, for example, a vertical cylinder, which is then tightly closed. At this point, the pressure within the cylinder, termed the initial pressure, is that of the atmosphere. Air under pressure is then introduced until the gauge pressure is l5 pounds per square inch, this being called the intermediate pressure. Then, without diminishing the intermediate pressure, the detergent solution is forced into the textile material at a still higher pressure, the final pressure being about 45 pounds per square inch.

After a short time, usually l0 to 30 seconds, the system is vented to the atmosphere, the exhaust pressure being atmospheric. The air, under the intermediate pressure in the recesses of the fabric, and further compressed by the final pressure to about one-fourth of its original -volume, expands, driving before it the detergent solution including that which has penetrated the fabric, the solution carrying with it the dirt and soil which it has removed from the fabric and leaving the cylinder through, preferably, a bottom outlet. The detergent solution is then discarded. The cylinder is again closed, the air pressure is again raised to 15 pounds, gauge, and the cycle is repeated with new detergent solution. The number of detersive cycles may be from about two to seven or eight, as experience shows to be necessary with a particular kind of soiled fabric.

The detersive step is followed by a rinsing step. The procedure is the same except that water replaces detergent solution in the cycle. Two to four rinsing cycles are usually sufficient.

If it is found desirable to remove water-soluble soil before the detersive step, this is done by subjecting the soiled fabric to Ione or more rinsing cycles. If the nature of the fabric and the soil will permit, it is usually best to apply the water in all rinsing cycles at a fairly high temperature, for example, 60 C.

In the following examples, the details of various types of cleaning operations are given, the procedure being about as above described.

Example 1.-Washz'lng of Silk and Wooen Fabrics Detergent formula: Percent Non-ionic detergent 20.0 Tetrasodium pyrophosphate 40.0 Sodium bicarbonate 38.0 Sodium carboxymethylcellulose 2.0

The non-ionic detergent is prepared from coconut oil fatty acids which have reacted with ethylene oxide to give polyoxyethylene esters carrying, for each fatty acid residue, 10 to l5 ethylene oxide groups. About 1 percent of the above formula is dissolved in water, the pH being about 7.5. Two preliminary soaking or rinsing cycles are given, then five detersive cycles, then two rinsing cycles, all liquids being at 20 to 30 C.

Example 2.-Washng of Ordinary Household Laundry Detergent formula: Percent Dodecylbenzene sodium sulfonate 24 Sodium sulfate 40 Sodium tripolyphosphate 20 Sodium sesquicarbonate 14 Sodium carboxymethylcellulose 2 The above formula is dissolved in water to make a l percent detergent solution, pH about 8.0. Two preliminary rinsing cycles are given, then six detersive cycles with the detergent solution just described, then four rinsing cycles with water. The preliminary rinses are with water at about 20 C., the detergent solution is at 60 C. and the final rinse water at 60 C.

Example 3.-Ordnary Household Laundry This procedure is exactly the same as in Example 2, except that, the detergent solution is a 1.25 percent solution of an unbuilt soap consisting of the sodium salts of the coconut oil fatty acids.

Example 4.-Wasl1ing of Oil-Stained Work Clothes Detergent formula: Percent Laundry soap 70 Sodium metasilicate 10 Sodium carbonate 15 Trisodium phosphate 5 The laundry soap is a mixture of the sodium salts of the tallow acids, mainly palmitate, stearate and oleate. The formula just given is made into a 2.5 percent detergent solution for use in the present example. Two preliminary soakings or rinsings with water at 60 C. are given, then eight detersive cycles with the solution at 80 C., then four water rinsing cycles at 60 C.

Example 5.--Cleaning Woolen Fabrics With Triclzloroethylene The procedure is the same as in Examples 1-4 except that the trichloroethylene is at room temperature and there is no preliminary or final rinsing cycle. The cleaning cycle is repeated a sufficient number of times until the desired degree of cleanness is attained.

Many of the synthetic detergent materials work about as well in cold Water as in hot. It is seen, therefore, that in many instances the temperature of the detergent solution is not an important consideration and may range from about 20 C. to 100 C.

The air compressor and the pumps for detergent solution and rinse water may be located at va distance from the vessel in which the textile materials are being cleaned. In the case of a commercial laundry, operating a number of washing machines, all may be served by a single set of compressors and pumps.

The various operations of the present invention are very fast. With full automatic operation, a single detersive or rinsing cycle may be completed in as little as 60 seconds. Means for such automatic control are well understood and are currently in use on a large scale in other types of laundry equipment and elsewhere.

The pressures used in the process are not critical; the intermediate pressure may be from about 5 to about 20, and the inal pressure from about 20 to about 50 pounds per square inch above atmospheric.

The use of an intermediate, superatmospheric gaseous pressure before introducing the cleaning liquid or rinse water is an important and essential part of the present invention. This pressure permits of very rapid ejection of the cleaning liquid or rinse from the fabric and container. The efliciency of the detergent and rinse cycles is greatly improved and the washing time greatly reduced thereby.

In commercial installations where a number of Washing machines are in use, the present process makes possible a saving in detergent solution. The spent detergent solution from the first detersive cycle carries the greater part of the soil and is normally discarded. The second detergent solution from No. 1 machine carries much less soil and may be used in the first detergent cycle in the No. 2 machine. Similarly, the third detergent solution from machine No. 1 becomes the second detergent solution for machine No. 2 and the first detergent solution for machine No. 3.

In this way, a considerable economy may be effected with respect to consumption of detergent material. The only detergent solution discarded is the dirty solution from the first detersive cycle of each machine. It should be noted that, in all cases, the last detersive cycle employs perfectly clean detergent solution on fabrics which are already rather well cleaned.

One of the most serious problems in the laundry industry is what is known as re-deposition, that is, the removal of `soil from the dirtier portions of the fabric and the redeposition of the same soil on a relatively clean portion of the same, or another, fabric. In an ordinary washing machine, the fabric and the more or less dirty detergent solution come to equilibrium, with respect to dirt, some dirt being removed from dirty fabric and a portion of this being deposited on clean fabric. This is to be expected as the detersive operation in an ordinary washing machine, domestic or commercial, consists of a haphazard tumbling of the soiled clothes in a somewhat dirty solution. A counter-current movement of clothes and detergent solution would offer no advantage as it brings the cleanest portions of the clothes into contact with the dirtiest detergent solution.

To offset the yellowing of clothes from both unremoved and re-deposited dirt, the industry has used various expedients, such as, laundry blueing and, in recent years, the so-called direct white dyes, pale blue dyes the color of which partially masks the yellowishness of the laundered material.

In the present invention, re-deposition is reduced to negligible proportions. In the detersive cycle, when the final pressure is reduced to atmospheric, the detergent solution within the dirtier parts of the fabric is purged out by the expansion of the compressed and entrapped air, carrying with it such dirt las has been removed. At the same time, a fairly clean detergent solution is purging from the cleaner parts of the fabric and this acts as a barrier to protect the clean fabric from contact with dirty solution.

It will be evident that the apparatus in which fabrics are cleaned in accordance with the present invention has no moving parts. The container may be packed full of fabrics since no space is required for tumbling action, as in other machines.

The principal advantages of the present process over those now in use are, (1) it cleans fabrics rnuch more thoroughly and (2) it does it in much less time.

Compressed air has often been used in connection with detergent operations, for example, to maintain a constant pressure on the system. It has never been used, however, in the manner of the present invention as described in column 1 above.

What I claim is:

1. In a process for cleaning textile materials, the following sequence of steps, (1) placing the soiled material in a container which is then tightly closed, (2) building up within the container and within the textile material an intermediate gaseous pressure higher than the pressure against which the gas will later be released, (3) without reducing said intermediate gaseous pressure, introducing a cleaning liquid into the fabric and the container at a still higher nal pressure, thus compressing the gas within the textile material into still smaller volume with entry of the cleaning liquid into the interstices and capillaries of the textile material, (4) expelling most of the soilbearing cleaning liquid from the recesses of the fabric and from the container solely by means of the compressed gas within the fabric and container by permitting said gas to expand against a lower pressure external to the container, and (5) repeating the cycle at least once with fresh cleaning liquid.

2. The process of claim 1 wherein the cleaning liquid is an organic cleaning liquid.

3. In a process for cleaning textile materials, the following sequence of steps, 1) placing the soiled textile material in a container which is then tightly closed, (2) building up within the textile material and container an intermediate gaseous pressure higher than the pressure against which the gas will later be released, (3) without reducing said intermediate gaseous pressure, introducing a detergent solution into the textile material and the container at a still higher final pressure, thus compressing the gas into smaller volume with entry of the detergent solution into the interstices and capillaries of the textile material, (4) expelling most of the soil-bearing detergent solution from the recesses of the fabric and from the container solely by means of the compressed gas Within the fabric and container by permitting said gas to expand against a lower pressure external to the container, (5) repeating the cleaning cycle at least once with fresh detergent solution and (6) rinsing the cleaned textile material by repeating the cycle with detergent solution replaced by water.

4. The process of claim 3 wherein the detergent is selected from the class consisting of anionic and non-ionic detergents.

References Cited in the file of this patent UNITED STATES PATENTS 1,678,089 Ullmann July 29, 1928 1,948,565 Farber Feb. 27, 1934 FOREIGN PATENTS 499,539 Great Britain Ian. 25, 1939 679,687 Great Britain Sept. 24, 1952 800,986 Great Britain Sept. 3, 1958 

1. IN A PROCESS FOR CLEANING TEXTILE MATERIALS, THE FOLLOWING SEQUENCE OF STEPS, (1) PLACING THE SOILED MATERIAL IN A CONTAINER WHICH IS THEN TIGHTLY CLOSED, (2) BUILDING UP WITHIN THE CONTAINER AND WITHIN THE TEXTILE MATERIAL AN INTERMEDIATE GASEOUS PRESSURE HIGHER THAN THE PRESSURE AGAINST WHICH THE GAS WILL LATER BE RELEASED, (3) WITHOUT REDUCING SAID INTERMEDIATE GASEOUS PRESSURE, INTRODUCING A CLEANING LIQUID INTO THE FABRIC AND THE CONTAINER AT A STILL HIGHER FINAL PRESSURE, THUS COMPRESSING THE GAS WITHIN THE TEXTILE MATERIAL INTO STILL SMALLER; VOLUME WITH ENTRY OF THE CLEANING LIQUID INTO THE INTERSTICES AND CAPILLARIES OF THE TEXTILE MATERIAL, (4) EXPELLING MOST OF THE SOILBEARING CLEANING LIQUID FROM THE RECESSES OF THE FABRIC AND FROM THE CONTAINER SOLELY BY MEANS OF THE COMPRESSED GAS WITHIN THE FABRIC AND CONTAINER BY PERMITTING SAID GAS TO EXPAND AGAINST A LOWER PRESSURE EXTERNAL TO THE CONTAINER, AND (5) REPEATING THE CYCLE AT LEAST ONCE WITH FRESH CLEANING LIQUID. 